Air purification apparatuses have been widely used in many circumstances, such as offices, workshops or medical facilities, for removing pollutants in air and providing purified air to people. The air purification apparatuses typically comprise a filtration component, which collects the pollutants, such as solid particles or organic pollutants, when air flows therethrough. However, the conventional air purification apparatuses are generally disposed in indoor spaces, and therefore they can only be used to purify indoor air. When the indoor air quality is poor, such air purification apparatus cannot produce clean air as required because the filtration capability of the filtration component is limited.